Techniques for clock synchronization and control in wireless power delivery environments

ABSTRACT

Techniques for automated clock synchronization and control are discussed herein. For example, the techniques can include monitoring of transmissions for ‘known’ events and identifying timing or frequencies of such events. Deviations in the timing or frequencies of the events from expected times or frequencies may indicate that wireless power transmission system and receiver clocks are not synchronized. The deviations can be used to synchronize the clock for optimum wireless power transfer. Techniques are also described for enhancing clock control mechanisms to provide additional means for managing the adjustments of the clocks, as well as for enabling wireless power transmission systems to mimic client clock offsets for effective synchronization of events (e.g., beacon signals).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit from U.S. ProvisionalPatent Application Ser. No. 62/187,190 titled “SYSTEMS AND METHODS FORIMPROVING WIRELESS CHARGING EFFICIENCY” filed on Jun. 30, 2015, which isexpressly incorporated by reference herein.

TECHNICAL FIELD

The technology described herein relates generally to the field ofwireless power transmission and, more specifically, to techniques forautomated clock synchronization and control in wireless power deliveryenvironments.

BACKGROUND

Many electronic devices are powered by batteries. Rechargeable batteriesare often used to avoid the cost of replacing conventional dry-cellbatteries and to conserve precious resources. However, rechargingbatteries with conventional rechargeable battery chargers requiresaccess to an alternating current (AC) power outlet, which is sometimesnot available or not convenient. It would, therefore, be desirable toderive power for electronics wirelessly.

Accordingly, a need exists for technology that overcomes the problemdemonstrated above, as well as one that provides additional benefits.The examples provided herein of some prior or related systems and theirassociated limitations are intended to be illustrative and notexclusive. Other limitations of existing or prior systems will becomeapparent to those of skill in the art upon reading the followingDetailed Description.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention are illustrated by wayof example and not limitation in the figures of the accompanyingdrawings, in which like references indicate similar elements.

FIG. 1 depicts a block diagram including an example wireless powerdelivery environment illustrating wireless power delivery from one ormore wireless power transmission systems to various wireless deviceswithin the wireless power delivery environment in accordance with someembodiments.

FIG. 2 depicts a sequence diagram illustrating example operationsbetween a wireless power transmission system and a wireless receiverclient for commencing wireless power delivery in accordance with someembodiments.

FIG. 3 depicts a block diagram illustrating example components of awireless power transmission system in accordance with some embodiments.

FIG. 4 depicts a block diagram illustrating example components of awireless power receiver client in accordance with some embodiments.

FIGS. 5A and 5B depict diagrams illustrating an example multipathwireless power delivery environment in accordance with some embodiments.

FIGS. 6A and 6B depict sequence diagrams illustrating example operationsfor event-time based synchronization of a wireless power receiver clientwith a wireless power transmission system in a wireless power deliveryenvironment, according to some embodiments.

FIG. 7 depicts a sequence diagram illustrating example operations forsynchronizing a wireless power receiver client with a wireless powertransmission system in a wireless power delivery environment, accordingto some embodiments.

FIGS. 8A and 8B depict sequence diagrams illustrating example operationsfor phase- or frequency-based synchronization of a wireless powerreceiver client with a wireless power transmission system in a wirelesspower delivery environment, according to some embodiments.

FIGS. 9A and 9B depict sequence diagrams illustrating example operationsfor phase- or frequency-based synchronization of a wireless powerreceiver client with a wireless power transmission system in a wirelesspower delivery environment, according to some embodiments.

FIG. 10 depicts a flow diagram illustrating an example process forfacilitating synchronization between a wireless power receiver clientand a wireless power transmission system in a wireless power deliveryenvironment, according to some embodiments.

FIG. 11 depicts a block diagram illustrating example components of arepresentative mobile device or tablet computer with one or morewireless power receiver clients in the form of a mobile (or smart) phoneor tablet computer device in accordance with some embodiments.

FIG. 12 depicts a diagrammatic representation of a machine, in theexample form, of a computer system within which a set of instructions,for causing the machine to perform any one or more of the methodologiesdiscussed herein, may be executed.

DETAILED DESCRIPTION

The following description and drawings are illustrative and are not tobe construed as limiting. Numerous specific details are described toprovide a thorough understanding of the disclosure. However, in certaininstances, well-known or conventional details are not described in orderto avoid obscuring the description. References to one or an embodimentin the present disclosure can be, but not necessarily are, references tothe same embodiment; and, such references mean at least one of theembodiments.

Reference in this specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the disclosure. The appearances of the phrase “in one embodiment” invarious places in the specification are not necessarily all referring tothe same embodiment, nor are separate or alternative embodimentsmutually exclusive of other embodiments. Moreover, various features aredescribed which may be exhibited by some embodiments and not by others.Similarly, various requirements are described which may be requirementsfor some embodiments but no other embodiments.

The terms used in this specification generally have their ordinarymeanings in the art, within the context of the disclosure, and in thespecific context where each term is used. Certain terms that are used todescribe the disclosure are discussed below, or elsewhere in thespecification, to provide additional guidance to the practitionerregarding the description of the disclosure. For convenience, certainterms may be highlighted, for example using italics and/or quotationmarks. The use of highlighting has no influence on the scope and meaningof a term; the scope and meaning of a term is the same, in the samecontext, whether or not it is highlighted. It will be appreciated thatsame thing can be said in more than one way.

Consequently, alternative language and synonyms may be used for any oneor more of the terms discussed herein, nor is any special significanceto be placed upon whether or not a term is elaborated or discussedherein. Synonyms for certain terms are provided. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification, including examples of any termsdiscussed herein, is illustrative only, and is not intended to furtherlimit the scope and meaning of the disclosure or of any exemplifiedterm. Likewise, the disclosure is not limited to various embodimentsgiven in this specification.

Without intent to further limit the scope of the disclosure, examples ofinstruments, apparatus, methods and their related results according tothe embodiments of the present disclosure are given below. Note thattitles or subtitles may be used in the examples for convenience of areader, which in no way should limit the scope of the disclosure. Unlessotherwise defined, all technical and scientific terms used herein havethe same meaning as commonly understood by one of ordinary skill in theart to which this disclosure pertains. In the case of conflict, thepresent document, including definitions, will control.

I. Wireless Power Transmission System Overview/Architecture

FIG. 1 depicts a block diagram including an example wireless powerdelivery environment 100 illustrating wireless power delivery from oneor more wireless power transmission systems (WPTS) 101 a-n (alsoreferred to as “wireless power delivery systems”, “antenna arraysystems” and “wireless chargers”) to various wireless devices 102 a-nwithin the wireless power delivery environment 100, according to someembodiments. More specifically, FIG. 1 illustrates an example wirelesspower delivery environment 100 in which wireless power and/or data canbe delivered to available wireless devices 102 a-102 n having one ormore wireless power receiver clients 103 a-103 n (also referred toherein as “clients” and “wireless power receivers”). The wireless powerreceiver clients are configured to receive and process wireless powerfrom one or more wireless power transmission systems 101 a-101 n.Components of an example wireless power receiver client 103 are shownand discussed in greater detail with reference to FIG. 4.

As shown in the example of FIG. 1, the wireless devices 102 a-102 ninclude mobile phone devices and a wireless game controller. However,the wireless devices 102 a-102 n can be any device or system that needspower and is capable of receiving wireless power via one or moreintegrated power receiver clients 103 a-103 n. As discussed herein, theone or more integrated power receiver clients receive and process powerfrom one or more wireless power transmission systems 101 a-101 n andprovide the power to the wireless devices 102 a-102 n (or internalbatteries of the wireless devices) for operation thereof.

Each wireless power transmission system 101 can include multipleantennas 104 a-n, e.g., an antenna array including hundreds or thousandsof antennas, which are capable of delivering wireless power to wirelessdevices 102. In some embodiments, the antennas are adaptively-phasedradio frequency (RF) antennas. The wireless power transmission system101 is capable of determining the appropriate phases with which todeliver a coherent power transmission signal to the power receiverclients 103. The array is configured to emit a signal (e.g., continuouswave or pulsed power transmission signal) from multiple antennas at aspecific phase relative to each other. It is appreciated that use of theterm “array” does not necessarily limit the antenna array to anyspecific array structure. That is, the antenna array does not need to bestructured in a specific “array” form or geometry. Furthermore, as usedherein he term “array” or “array system” may be used include related andperipheral circuitry for signal generation, reception and transmission,such as radios, digital logic and modems. In some embodiments, thewireless power transmission system 101 can have an embedded Wi-Fi hubfor data communications via one or more antennas or transceivers.

The wireless devices 102 can include one or more receive power clients103. As illustrated in the example of FIG. 1, power delivery antennas104 a-104 n are shown. The power delivery antennas 104 a are configuredto provide delivery of wireless radio frequency power in the wirelesspower delivery environment. In some embodiments, one or more of thepower delivery antennas 104 a-104 n can alternatively or additionally beconfigured for data communications in addition to or in lieu of wirelesspower delivery. The one or more data communication antennas areconfigured to send data communications to and receive datacommunications from the power receiver clients 103 a-103 n and/or thewireless devices 102 a-102 n. In some embodiments, the datacommunication antennas can communicate via Bluetooth™, Wi-Fi™, ZigBee™,etc. Other data communication protocols are also possible.

Each power receiver client 103 a-103 n includes one or more antennas(not shown) for receiving signals from the wireless power transmissionsystems 101 a-101 n. Likewise, each wireless power transmission system101 a-101 n includes an antenna array having one or more antennas and/orsets of antennas capable of emitting continuous wave or discrete (pulse)signals at specific phases relative to each other. As discussed above,each the wireless power transmission systems 101 a-101 n is capable ofdetermining the appropriate phases for delivering the coherent signalsto the power receiver clients 102 a-102 n. For example, in someembodiments, coherent signals can be determined by computing the complexconjugate of a received beacon (or calibration) signal at each antennaof the array such that the coherent signal is phased for deliveringpower to the particular power receiver client that transmitted thebeacon (or calibration) signal.

Although not illustrated, each component of the environment, e.g.,wireless device, wireless power transmission system, etc., can includecontrol and synchronization mechanisms, e.g., a data communicationsynchronization module. The wireless power transmission systems 101a-101 n can be connected to a power source such as, for example, a poweroutlet or source connecting the wireless power transmission systems to astandard or primary alternating current (AC) power supply in a building.Alternatively, or additionally, one or more of the wireless powertransmission systems 101 a-101 n can be powered by a battery or viaother mechanisms, e.g., solar cells, etc.

The power receiver clients 102 a-102 n and/or the wireless powertransmission systems 101 a-101 n are configured to operate in amultipath wireless power delivery environment. That is, the powerreceiver clients 102 a-102 n and the wireless power transmission systems101 a-101 n are configured to utilize reflective objects 106 such as,for example, walls or other RF reflective obstructions within range totransmit beacon (or calibration) signals and/or receive wireless powerand/or data within the wireless power delivery environment. Thereflective objects 106 can be utilized for multi-directional signalcommunication regardless of whether a blocking object is in the line ofsight between the wireless power transmission system and the powerreceiver client.

As described herein, each wireless device 102 a-102 n can be any systemand/or device, and/or any combination of devices/systems that canestablish a connection with another device, a server and/or othersystems within the example environment 100. In some embodiments, thewireless devices 102 a-102 n include displays or other outputfunctionalities to present data to a user and/or input functionalitiesto receive data from the user. By way of example, a wireless device 102can be, but is not limited to, a video game controller, a serverdesktop, a desktop computer, a computer cluster, a mobile computingdevice such as a notebook, a laptop computer, a handheld computer, amobile phone, a smart phone, a PDA, a Blackberry device, a Treo, and/oran iPhone, etc. By way of example and not limitation, the wirelessdevice 102 can also be any wearable device such as watches, necklaces,rings or even devices embedded on or within the customer. Other examplesof a wireless device 102 include, but are not limited to, safety sensors(e.g., fire or carbon monoxide), electric toothbrushes, electronic doorlock/handles, electric light switch controller, electric shavers, etc.

Although not illustrated in the example of FIG. 1, the wireless powertransmission system 101 and the power receiver clients 103 a-103 n caneach include a data communication module for communication via a datachannel. Alternatively, or additionally, the power receiver clients 103a-103 n can direct the wireless devices 102.1-102.n to communicate withthe wireless power transmission system via existing data communicationsmodules. In some embodiments the beacon signal, which is primarilyreferred to herein as a continuous waveform, can alternatively oradditionally take the form of a modulated signal.

FIG. 2 is a sequence diagram 200 illustrating example operations betweena wireless power delivery system (e.g., WPTS 101) and a wireless powerreceiver client (e.g., wireless power receiver client 103) forestablishing wireless power delivery in a multipath wireless powerdelivery, according to an embodiment. Initially, communication isestablished between the wireless power transmission system 101 and thepower receiver client 103. The initial communication can be, forexample, a data communication link that is established via one or moreantennas 104 of the wireless power transmission system 101. Asdiscussed, in some embodiments, one or more of the antennas 104 a-104 ncan be data antennas, wireless power transmission antennas, ordual-purpose data/power antennas. Various information can be exchangedbetween the wireless power transmission system 101 and the wirelesspower receiver client 103 over this data communication channel. Forexample, wireless power signaling can be time sliced among variousclients in a wireless power delivery environment. In such cases, thewireless power transmission system 101 can send beacon scheduleinformation, e.g., Beacon Beat Schedule (BBS) cycle, power cycleinformation, etc., so that the wireless power receiver client 103 knowswhen to transmit (broadcast) its beacon signals and when to listen forpower, etc.

Continuing with the example of FIG. 2, the wireless power transmissionsystem 101 selects one or more wireless power receiver clients forreceiving power and sends the beacon schedule information to the selectpower receiver clients 103. The wireless power transmission system 101can also send power transmission scheduling information so that thepower receiver client 103 knows when to expect (e.g., a window of time)wireless power from the wireless power transmission system. The powerreceiver client 103 then generates a beacon (or calibration) signal andbroadcasts the beacon during an assigned beacon transmission window (ortime slice) indicated by the beacon schedule information, e.g., BeaconBeat Schedule (BBS) cycle. As discussed herein, the wireless powerreceiver client 103 include one or more antennas (or transceivers) whichhave a radiation and reception pattern in three-dimensional spaceproximate to the wireless device 102 in which the power receiver client103 is embedded.

The wireless power transmission system 101 receives the beacon from thepower receiver client 103 and detects and/or otherwise measures thephase (or direction) from which the beacon signal is received atmultiple antennas. The wireless power transmission system 101 thendelivers wireless power to the power receiver client 103 from themultiple antennas 103 based on the detected or measured phase (ordirection) of the received beacon at each of the corresponding antennas.In some embodiments, the wireless power transmission system 101determines the complex conjugate of the measured phase of the beacon anduses the complex conjugate to determine a transmit phase that configuresthe antennas for delivering and/or otherwise directing wireless power tothe power receiver client 103 via the same path over which the beaconsignal was received from the power receiver client 103.

In some embodiments, the wireless power transmission system 101 includesmany antennas; one or more of which are used to deliver power to thepower receiver client 103. The wireless power transmission system 101can detect and/or otherwise determine or measure phases at which thebeacon signals are received at each antenna. The large number ofantennas may result in different phases of the beacon signal beingreceived at each antenna of the wireless power transmission system 101.As discussed above, the wireless power transmission system 101 candetermine the complex conjugate of the beacon signals received at eachantenna. Using the complex conjugates, one or more antennas may emit asignal that takes into account the effects of the large number ofantennas in the wireless power transmission system 101. In other words,the wireless power transmission system 101 can emit a wireless powertransmission signal from the one or more antennas in such a way as tocreate an aggregate signal from the one or more of the antennas thatapproximately recreates the waveform of the beacon in the oppositedirection. Said another way, the wireless power transmission system 101can deliver wireless RF power to the client device via the same pathsover which the beacon signal is received at the wireless powertransmission system 101. These paths can utilize reflective objects 106within the environment. Additionally, the wireless power transmissionsignals can be simultaneously transmitted from the wireless powertransmission system 101 such that the wireless power transmissionsignals collectively match the antenna radiation and reception patternof the client device in a three-dimensional (3D) space proximate to theclient device.

As shown, the beacon (or calibration) signals can be periodicallytransmitted by power receiver clients 103 within the power deliveryenvironment according to, for example, the BBS, so that the wirelesspower transmission system 101 can maintain knowledge and/or otherwisetrack the location of the power receiver clients 103 in the wirelesspower delivery environment. The process of receiving beacon signals froma wireless power receiver client at the wireless power transmissionsystem and, in turn, responding with wireless power directed to thatparticular client is referred to herein as retrodirective wireless powerdelivery.

Furthermore, as discussed herein, wireless power can be delivered inpower cycles defined by power schedule information. A more detailedexample of the signaling required to commence wireless power delivery isdescribed now with reference to FIG. 3.

FIG. 3 is a block diagram illustrating example components of a wirelesspower transmission system 300, in accordance with an embodiment. Asillustrated in the example of FIG. 3, the wireless charger 300 includesa master bus controller (MBC) board and multiple mezzanine boards thatcollectively comprise the antenna array. The MBC includes control logic310, an external data interface (I/F) 315, an external power interface(I/F) 320, a communication block 330 and proxy 340. The mezzanine (orantenna array boards 350) each include multiple antennas 360 a-360 n.Some or all of the components can be omitted in some embodiments.Additional components are also possible. For example, in someembodiments only one of communication block 330 or proxy 340 may beincluded.

The control logic 310 is configured to provide control and intelligenceto the array components. The control logic 310 may comprise one or moreprocessors, FPGAs, memory units, etc., and direct and control thevarious data and power communications. The communication block 330 candirect data communications on a data carrier frequency, such as the basesignal clock for clock synchronization. The data communications can beBluetooth™, Wi-Fi™, ZigBee™, etc., including combinations or variationsthereof. Likewise, the proxy 340 can communicate with clients via datacommunications as discussed herein. The data communications can be, byway of example and not limitation, Bluetooth™, Wi-Fi™, ZigBee™, etc.Other communication protocols are possible.

In some embodiments, the control logic 310 can also facilitate and/orotherwise enable data aggregation for Internet of Things (IoT) devices.In some embodiments, wireless power receiver clients can access, trackand/or otherwise obtain IoT information about the device in which thewireless power receiver client is embedded and provide that IoTinformation to the wireless power transmission system 300 over a dataconnection. This IoT information can be provided to via an external datainterface 315 to a central or cloud-based system (not shown) where thedata can be aggregated, processed, etc. For example, the central systemcan process the data to identify various trends across geographies,wireless power transmission systems, environments, devices, etc. In someembodiments, the aggregated data and or the trend data can be used toimprove operation of the devices via remote updates, etc. Alternatively,or additionally, in some embodiments, the aggregated data can beprovided to third party data consumers. In this manner, the wirelesspower transmission system acts as a Gateway or Enabler for the IoTs. Byway of example and not limitation, the IoT information can includecapabilities of the device in which the wireless power receiver clientis embedded, usage information of the device, power levels of thedevice, information obtained by the device or the wireless powerreceiver client itself, e.g., via sensors, etc.

The external power interface 320 is configured to receive external powerand provide the power to various components. In some embodiments, theexternal power interface 320 may be configured to receive a standardexternal 24 Volt power supply. In other embodiments, the external powerinterface 320 can be, for example, 120/240 Volt AC mains to an embeddedDC power supply which sources the required 12/24/48 Volt DC to providethe power to various components. Alternatively, the external powerinterface could be a DC supply which sources the required 12/24/48 VoltsDC. Alternative configurations are also possible.

In operation, the master bus controller (MBC), which controls thewireless power transmission system 300, receives power from a powersource and is activated. The MBC then activates the proxy antennaelements on the wireless power transmission system and the proxy antennaelements enter a default “discovery” mode to identify available wirelessreceiver clients within range of the wireless power transmission system.When a client is found, the antenna elements on the wireless powertransmission system power on, enumerate, and (optionally) calibrate.

The MBC then generates beacon transmission scheduling information andpower transmission scheduling information during a scheduling process.The scheduling process includes selection of power receiver clients. Forexample, the MBC can select power receiver clients for powertransmission and generate a Beacon Beat Schedule (BBS) cycle and a PowerSchedule (PS) for the selected wireless power receiver clients. Asdiscussed herein, the power receiver clients can be selected based ontheir corresponding properties and/or requirements.

In some embodiments, the MBC can also identify and/or otherwise selectavailable clients that will have their status queried in the ClientQuery Table (CQT). Clients that are placed in the CQT are those on“standby”, e.g., not receiving a charge. The BBS and PS are calculatedbased on vital information about the clients such as, for example,battery status, current activity/usage, how much longer the client hasuntil it runs out of power, priority in terms of usage, etc.

The Proxy AE broadcasts the BBS to all clients. As discussed herein, theBBS indicates when each client should send a beacon. Likewise, the PSindicates when and to which clients the array should send power to andwhen clients should listen for wireless power. Each client startsbroadcasting its beacon and receiving power from the array per the BBSand PS. The Proxy can concurrently query the Client Query Table to checkthe status of other available clients. In some embodiments, a client canonly exist in the BBS or the CQT (e.g., waitlist), but not in both. Theinformation collected in the previous step continuously and/orperiodically updates the BBS cycle and/or the PS.

FIG. 4 is a block diagram illustrating example components of a wirelesspower receiver client, in accordance with some embodiments. Asillustrated in the example of FIG. 4, the receiver 400 includes controllogic 410, battery 420, an IoT control module 425, communication block430 and associated antenna 470, power meter 440, rectifier 450, acombiner 455, beacon signal generator 460, beacon coding unit 462 and anassociated antenna 480, and switch 465 connecting the rectifier 450 orthe beacon signal generator 460 to one or more associated antennas 490a-n. Some or all of the components can be omitted in some embodiments.For example, in some embodiments, the wireless power receiver clientdoes not include its own antennas but instead utilizes and/or otherwiseshares one or more antennas (e.g., Wi-Fi antenna) of the wireless devicein which the wireless power receiver client is embedded. Moreover, insome embodiments, the wireless power receiver client may include asingle antenna that provides data transmission functionality as well aspower/data reception functionality. Additional components are alsopossible.

A combiner 455 receives and combines the received power transmissionsignals from the power transmitter in the event that the receiver 400has more than one antenna. The combiner can be any combiner or dividercircuit that is configured to achieve isolation between the output portswhile maintaining a matched condition. For example, the combiner 455 canbe a Wilkinson Power Divider circuit. The rectifier 450 receives thecombined power transmission signal from the combiner 455, if present,which is fed through the power meter 440 to the battery 420 forcharging. In other embodiments, each antenna's power path can have itsown rectifier 450 and the DC power out of the rectifiers is combinedprior to feeding the power meter 440. The power meter 440 can measurethe received power signal strength and provides the control logic 410with this measurement.

Battery 420 can include protection circuitry and/or monitoringfunctions. Additionally, the battery 420 can include one or morefeatures, including, but not limited to, current limiting, temperatureprotection, over/under voltage alerts and protection, and coulombmonitoring.

The control logic 410 can receive the battery power level from thebattery 420 itself. The control logic 410 may also transmit/receive viathe communication block 430 a data signal on a data carrier frequency,such as the base signal clock for clock synchronization. The beaconsignal generator 460 generates the beacon signal, or calibration signal,transmits the beacon signal using either the antenna 480 or 490 afterthe beacon signal is encoded.

It may be noted that, although the battery 420 is shown as charged by,and providing power to, the receiver 400, the receiver may also receiveits power directly from the rectifier 450. This may be in addition tothe rectifier 450 providing charging current to the battery 420, or inlieu of providing charging. Also, it may be noted that the use ofmultiple antennas is one example of implementation and the structure maybe reduced to one shared antenna.

In some embodiments, the control logic 410 and/or the IoT control module425 can communicate with and/or otherwise derive IoT information fromthe device in which the wireless power receiver client 400 is embedded.Although not shown, in some embodiments, the wireless power receiverclient 400 can have one or more data connections (wired or wireless)with the device in which the wireless power receiver client 400 isembedded over which IoT information can be obtained. Alternatively, oradditionally, IoT information can be determined and/or inferred by thewireless power receiver client 400, e.g., via one or more sensors. Asdiscussed above, the IoT information can include, but is not limited to,information about the capabilities of the device in which the wirelesspower receiver client is embedded, usage information of the device inwhich the wireless power receiver client is embedded, power levels ofthe battery or batteries of the device in which the wireless powerreceiver client is embedded, and/or information obtained or inferred bythe device in which the wireless power receiver client is embedded orthe wireless power receiver client itself, e.g., via sensors, etc.

In some embodiments, a client identifier (ID) module 415 stores a clientID that can uniquely identify the power receiver client in a wirelesspower delivery environment. For example, the ID can be transmitted toone or more wireless power transmission systems when communication isestablished. In some embodiments, power receiver clients may also beable to receive and identify other power receiver clients in a wirelesspower delivery environment based on the client ID.

An optional motion sensor 495 can detect motion and signal the controllogic 410 to act accordingly. For example, a device receiving power mayintegrate motion detection mechanisms such as accelerometers orequivalent mechanisms to detect motion. Once the device detects that itis in motion, it may be assumed that it is being handled by a user, andwould trigger a signal to the array to either to stop transmittingpower, or to lower the power transmitted to the device. In someembodiments, when a device is used in a moving environment like a car,train or plane, the power might only be transmitted intermittently or ata reduced level unless the device is critically low on power.

FIGS. 5A and 5B depict diagrams illustrating an example multipathwireless power delivery environment 500, according to some embodiments.The multipath wireless power delivery environment 500 includes a useroperating a wireless device 502 including one or more wireless powerreceiver clients 503. The wireless device 502 and the one or morewireless power receiver clients 503 can be wireless device 102 of FIG. 1and wireless power receiver client 103 of FIG. 1 or wireless powerreceiver client 400 of FIG. 4, respectively, although alternativeconfigurations are possible. Likewise, wireless power transmissionsystem 501 can be wireless power transmission system 101 FIG. 1 orwireless power transmission system 300 of FIG. 3, although alternativeconfigurations are possible. The multipath wireless power deliveryenvironment 500 includes reflective objects 506 and various absorptiveobjects, e.g., users, or humans, furniture, etc.

Wireless device 502 includes one or more antennas (or transceivers) thathave a radiation and reception pattern 510 in three-dimensional spaceproximate to the wireless device 102. The one or more antennas (ortransceivers) can be wholly or partially included as part of thewireless device 102 and/or the wireless power receiver client (notshown). For example, in some embodiments one or more antennas, e.g.,Wi-Fi, Bluetooth, etc. of the wireless device 502 can be utilized and/orotherwise shared for wireless power reception. As shown in the exampleof FIGS. 5A and 5B, the radiation and reception pattern 510 comprises alobe pattern with a primary lobe and multiple side lobes. Other patternsare also possible.

The wireless device 502 transmits a beacon (or calibration) signal overmultiple paths to the wireless power transmission system 501. Asdiscussed herein, the wireless device 502 transmits the beacon in thedirection of the radiation and reception pattern 510 such that thestrength of the received beacon signal by the wireless powertransmission system, e.g., RSSI, depends on the radiation and receptionpattern 510. For example, beacon signals are not transmitted where thereare nulls in the radiation and reception pattern 510 and beacon signalsare the strongest at the peaks in the radiation and reception pattern510, e.g., peak of the primary lobe. As shown in the example of FIG. 5A,the wireless device 502 transmits beacon signals over five paths P1-P5.Paths P4 and P5 are blocked by reflective and/or absorptive object 506.The wireless power transmission system 501 receives beacon signals ofincreasing strengths via paths P1-P3. The bolder lines indicate strongersignals. In some embodiments the beacon signals are directionallytransmitted in this manner to, for example, avoid unnecessary RF energyexposure to the user.

A fundamental property of antennas is that the receiving pattern(sensitivity as a function of direction) of an antenna when used forreceiving is identical to the far-field radiation pattern of the antennawhen used for transmitting. This is a consequence of the reciprocitytheorem in electromagnetics. As shown in the example of FIGS. 5A and 5B,the radiation and reception pattern 510 is a three-dimensional lobeshape. However, the radiation and reception pattern 510 can be anynumber of shapes depending on the type or types, e.g., horn antennas,simple vertical antenna, etc. used in the antenna design. For example,the radiation and reception pattern 510 can comprise various directivepatterns. Any number of different antenna radiation and receptionpatterns are possible for each of multiple client devices in a wirelesspower delivery environment.

Referring again to FIG. 5A, the wireless power transmission system 501receives the beacon (or calibration) signal via multiple paths P1-P3 atmultiple antennas or transceivers. As shown, paths P2 and P3 are directline of sight paths while path P1 is a non-line of sight path. Once thebeacon (or calibration) signal is received by the wireless powertransmission system 501, the power transmission system 501 processes thebeacon (or calibration) signal to determine one or more receivecharacteristics of the beacon signal at each of the multiple antennas.For example, among other operations, the wireless power transmissionsystem 501 can measure the phases at which the beacon signal is receivedat each of the multiple antennas or transceivers.

The wireless power transmission system 501 processes the one or morereceive characteristics of the beacon signal at each of the multipleantennas to determine or measure one or more wireless power transmitcharacteristics for each of the multiple RF transceivers based on theone or more receive characteristics of the beacon (or calibration)signal as measured at the corresponding antenna or transceiver. By wayof example and not limitation, the wireless power transmitcharacteristics can include phase settings for each antenna ortransceiver, transmission power settings, etc.

As discussed herein, the wireless power transmission system 501determines the wireless power transmit characteristics such that, oncethe antennas or transceivers are configured, the multiple antennas ortransceivers are operable to transit a wireless power signal thatmatches the client radiation and reception pattern in thethree-dimensional space proximate to the client device. FIG. 5Billustrates the wireless power transmission system 501 transmittingwireless power via paths P1-P3 to the wireless device 502.Advantageously, as discussed herein, the wireless power signal matchesthe client radiation and reception pattern 510 in the three-dimensionalspace proximate to the client device. Said another way, the wirelesspower transmission system will transmit the wireless power signals inthe direction in which the wireless power receiver has maximum gain,e.g., will receive the most wireless power. As a result, no signals aresent in directions in which the wireless power receiver cannot receiver,e.g., nulls and blockages. In some embodiments, the wireless powertransmission system 501 measures the RSSI of the received beacon signaland if the beacon is less than a threshold value, the wireless powertransmission system will not send wireless power over that path.

The three paths shown in the example of FIGS. 5A and 5B are illustratedfor simplicity, it is appreciated that any number of paths can beutilized for transmitting power to the wireless device 502 depending on,among other factors, reflective and absorptive objects in the wirelesspower delivery environment.

II. Clock Synchronization in Wireless Power Delivery Environments

Clock synchronization between wireless power receivers and wirelesspower transmission systems in a wireless power delivery environment isimperative for optimum wireless power transfers. Over time, frequencyand clock skew differences between wireless power receiver clients and awireless power transmission system can reduce or, in some instances,completely preclude wireless power transfers. Even minor differences inthe clocks may introduce delays during the discovery and beaconingprocesses resulting in reduced system efficiency.

Techniques for automated clock synchronization and control are discussedherein. For example, the techniques can include monitoring oftransmissions for ‘known’ events and identifying timing or frequenciesof such events. Deviations in the timing or frequencies of the eventsfrom expected times or frequencies may indicate that wireless powertransmission system and receiver clocks are not synchronized. Thedeviations can be used to synchronize the clock for optimum wirelesspower transfer. Techniques are also described for enhancing clockcontrol mechanisms to provide additional means for managing theadjustments of the clocks, as well as for enabling wireless powertransmission systems to mimic client clock offsets for effectivesynchronization of events (e.g., beacon signals).

FIGS. 6A and 6B depict sequence diagrams illustrating example operationsfor event-time based synchronization of a wireless power receiver client(e.g., wireless power receiver client 103) with a wireless powertransmission system (e.g., WPTS 101) in a wireless power deliveryenvironment, according to some embodiments. The examples of FIGS. 6A and6B illustrate example operations between a single wireless powertransmission system and a single wireless power receiver client.However, as discussed herein, a wireless power delivery environment caninclude any number of wireless power transmission systems and any numberof wireless power receiver clients.

In order to address clock drift issues, the wireless power receiverclocks may synchronize with the wireless power transmission system dueto the fact that a single wireless power transmission system typicallyservices multiple wireless power receiver clients. Accordingly, ratherthan modulating the charger clock for each device, in some embodiments,each wireless power receiver client may be synchronized to the timing ofa central wireless power transmission system. Additionally, although notshown, in wireless power delivery environments where multiple wirelesspower transmission systems exist, it may be beneficial to synchronizetheir clocks to one another to ensure successful communications (e.g.,handoff procedures). In some cases, the wireless power transmissionsystems may be set up in a master-slave arrangement where a singlewireless power transmission system is deemed the master device anddirects the other wireless power transmission system to synchronize withits reference clock. Alternatively, a cloud-based processing system orserver may be utilized to synchronize the various wireless powertransmission clocks.

Referring first to FIG. 6A, initially, at 610 and 611, the wirelesspower transmission system and the wireless power receiver client monitorevent schedule information. The event schedule information can include,for example, a beacon (or BBS) schedule, a power schedule, or otherevent schedule information related to wireless power transfers. In theexample of FIG. 6A, the wireless power transmission system monitors forexpected events and/or otherwise listens for events (e.g., a beacon ortone) expected to be received from the wireless power receiver client ata particular time or during a particular window of time. Similarly, thewireless power receiver monitors for transmission events (e.g., a beaconor tone) that it is scheduled to transmit.

At 612 and 613, the wireless power transmission system and the wirelesspower receiver client determine if an event is expected to be receivedand if an event is expected to be transmitted, respectively. Forexample, the wireless power transmission system can configure one ormore antennas to listen for an event transmitted by the wireless powerreceiver client and the wireless power receiver client can configure oneor more antennas to transmit the event to the wireless powertransmission system. At 615, the wireless power receiver clienttransmits the event (e.g., beacon). At 616, the wireless powertransmission system detects and/or otherwise receives the event andmakes a note (e.g., generates a timestamp) indicating a time that theevent was received.

At 618, the wireless power transmission system determines clockdifferential (or variance) information by comparing the time that theevent was received to a time that the event was expected to be received.The clock differential information can include timing differentialinformation (e.g., whether signal was early or late) as well asdifferential duration information (e.g., whether signal was short orlong). For example, the wireless power transmission system determines ifthe timing of the event was early or late, and if the transmission wasshort or long. If the wireless power receiver clock is running too fast,the event may be shorter than expected. Similarly, if the clock isrunning too slow, the event may be longer than expected. Conversely, ifthe wireless power receiver and wireless power transmission systemclocks are merely out of synch with one another, then the event may bereceived early or late.

Next, at 620, the wireless power transmission system determines whethersynchronization should be performed based on the clock differential. Forexample, a clock adjustment may be necessary if the clock differentialexceeds a predetermined clock differential threshold. In someembodiments, very small clock variances may be tolerable, especiallywhen the measured differences approach the magnitude of non-clockrelated timing factors (e.g., processing times, transmission travellatencies, etc.).

At 622, if synchronization should be performed, the wireless powertransmission system provides the clock differential (or variance)information to the wireless power receiver client. At 623, the wirelesspower receiver client receives the differential information and, at 625,adjusts its clock in accordance with the differential information.

Referring next to FIG. 6B, operations 610-620 are the same as theexample of FIG. 6A, however, in the example of FIG. 6B, rather thanadjusting the wireless power receiver client clock as shown in FIG. 6A,the wireless power transmission system adjusts its clock (for futurescheduled events) specifically for the particular wireless powerreceiver client in accordance with respective differential information.

FIG. 7 depicts a sequence diagram illustrating example operations forsynchronizing a wireless power receiver client (e.g., wireless powerreceiver client 103) with a wireless power transmission system (e.g.,WPTS 101) in a wireless power delivery environment, according to someembodiments. More specifically, the example of FIG. 7 illustrates atechnique for synchronizing multiple wireless power receiver clientswith both a wireless power transmission system and each other within awireless power delivery environment using a periodic synchronizationsignal. The example of FIG. 7 illustrates operations between a singlewireless power transmission system and a single wireless power receiverclient. However, as discussed herein, a wireless power deliveryenvironment can include any number of wireless power transmission systemand any number of wireless power receiver clients.

Typically, the wireless power receiver clients operate in one of threemodes: a beacon (or tone) mode; a power reception (or harvesting mode);and an idle mode. In some embodiments, the wireless power receiverclients operate in one of the beacon or harvesting modes. In such cases,the wireless power receiver clients can listen and synchronize withbeacons received from other clients. However, continuously operating ina harvesting mode can deplete system on resources. Accordingly, in someembodiments, e.g., when an idle mode is utilized, the wireless powerreceiver clients can include an additional synchronization mode thatoccurs periodically. During the synchronization mode, the wireless powerreceiver clients expect to receive a synchronization signal from awireless power transmission system and synchronize internal clocks basedon this synchronization signal. FIG. 7 illustrates an example of thissynchronization process.

Initially, at 710 and 711, the wireless power transmission system andthe wireless power receiver client monitor event schedule information.The event schedule information can include, for example, a beacon (orBBS) schedule, a power schedule, or other event schedule informationrelated to wireless power transfers. In the example of FIG. 7, the eventschedule includes a synchronization signal transmission schedule. Forexample, the wireless power transmission system can send a periodicsynchronization signal, e.g., once per second, to align each of thewireless power receiver clients that are receiving power from thewireless power transmission system to a single reference.

The wireless power transmission system monitors for transmission events(e.g., the periodic synchronization signal) that are scheduled to betransmitted to the wireless power receiver client. Likewise, thewireless power receiver client monitors its event schedule so that it islistening when the wireless power transmission system is broadcastingthe synchronization signal. At 712 and 713, the wireless powertransmission system and the wireless power receiver client determine ifan event is expected to be transmitted and if an event is expected to bereceived, respectively. If so, at 714, the wireless power transmissionsystem configures multiple antennas to broadcast the synchronizationsignal to one or more wireless power receiver clients.

At 715, a wireless power receiver client receives the synchronizationsignal and, at 817, the wireless power receiver client adjusts its clockin accordance with the synchronization signal. In some embodiments, theclock will be adjusted by either modifying the pre-scalar in a counter,or the fractional part of a Frac-N PLL (phase lock loop). Otheradjustments are also possible.

FIGS. 8A and 8B depict sequence diagrams illustrating example operationsfor phase- or frequency-based synchronization of a wireless powerreceiver client (e.g., wireless power receiver client 103) with awireless power transmission system (e.g., WPTS 101) in a wireless powerdelivery environment, according to some embodiments. More specifically,the examples of FIGS. 8A and 8B illustrate a wireless power receiverclient determining phase differential (or variance) information forfacilitating the phase- or frequency-based synchronization.

In some embodiments, rather than the wireless power transmission systemcollecting timing information in order to adjust the wireless powerreceiver client's clock, the client may compare frequencies of incomingdelivered power waves with its own radio frequency. The differencebetween the incoming frequency and the local frequency indicates a clockmismatch. The examples of FIGS. 8A and 8B illustrate example operationsbetween a single wireless power transmission system and a singlewireless power receiver client. However, as discussed herein, a wirelesspower delivery environment can include any number of wireless powertransmission system and any number of wireless power receiver clients.

Referring first to FIG. 8A, initially, at 810 and 811, the wirelesspower transmission system and the wireless power receiver client monitorevent schedule information. The event schedule information can include,for example, a beacon (or BBS) schedule, a power schedule, or otherevent schedule information related to wireless power transfers. In theexample of FIG. 8A, the wireless power transmission system monitors fortransmission events (e.g., wireless power) that are scheduled to betransmitted to the wireless power receiver client. Likewise, thewireless power receiver client monitors its power schedule (PS) so thatit is listening (e.g., in an energy harvest mode) when the wirelesspower transmission system is focusing energy on the wireless powerreceiver client.

At 812 and 813, the wireless power transmission system and the wirelesspower receiver client determine if an event is expected to betransmitted and if an event is expected to be received, respectively. Ifso, at 814, the wireless power transmission system configures multipleantennas to transfer wireless RF power to the wireless power receiverclient in the direction of a previously received beacon and, at 815, thewireless power receiver client receives the wireless power.

Next, at 817, the wireless power receiver client identifies the incomingfrequency of the wireless power signal and determines phase differential(or variance) information by comparing the incoming frequency with thelocal frequency transmission (e.g., beacon transmission) frequency. Aphase differential (or variance) indicates a clock mismatch. Again, adetermination is made whether there is mismatch in frequency (and thusclock synchronization) is sufficiently different to warrant anadjustment, at 819. For example, if the phase variance is greater than aphase variance threshold then, at 821, the wireless power receiverclient adjusts its clock in accordance with the phase differential (orvariance) information. In some embodiments, the clock will be adjustedby either modifying the pre-scalar in a counter, or the fractional partof a Frac-N PLL (phase lock loop). Other adjustments are also possible.

Referring next to FIG. 8B, operations 810-819 are the same as theexample of 8A, however, in the example of FIG. 8B, rather than adjustingthe wireless power receiver client clock as shown in FIG. 8A, thewireless power receiver client, at 821, notifies the wireless powerreceiver client by sending the phase variance information. The wirelesspower transmission system, at 822, receives the phase varianceinformation and adjusts its clock (for future scheduled events)specifically for the particular client in accordance with the phasedifferential (or variance) information.

FIGS. 9A and 9B depict sequence diagrams illustrating example operationsfor phase- or frequency-based synchronization of a wireless powerreceiver client (e.g., wireless power receiver client 103) with awireless power transmission system (e.g., WPTS 101) in a wireless powerdelivery environment, according to some embodiments. More specifically,the examples of FIGS. 9A and 9B illustrate a wireless power transmissionsystem determining phase differential (or variance) information forfacilitating the phase- or frequency-based synchronization.

In some embodiments, rather than the wireless power transmission systemcollecting timing information in order to adjust the wireless powerreceiver client's clock, the client may compare frequencies betweenincoming delivered power waves with its own radio frequency. Thedifference between the incoming frequency and the local frequencyindicates a clock mismatch. The examples of FIGS. 9A and 9B illustrateexample operations between a single wireless power transmission systemand a single wireless power receiver client; however, as discussedherein, a wireless power delivery environment can include any number ofwireless power transmission system and any number of wireless powerreceiver clients.

Referring first to FIG. 9A, initially, at 910 and 911, the wirelesspower transmission system and the wireless power receiver client monitorevent schedule information. The event schedule information can include,for example, a beacon (or BBS) schedule, a power schedule, or otherevent schedule information related to wireless power transfers. In theexample of FIG. 9A, the wireless power transmission system monitors forexpected events and/or otherwise listens for events (e.g., a beacon ortone) expected to be received from the wireless power receiver client ata particular time or during a particular window of time. Similarly, thewireless power receiver monitors for transmission events (e.g., a beaconor tone) that it is scheduled to transmit.

At 912 and 913, the wireless power transmission system and the wirelesspower receiver client determine if an event is expected to be receivedand if an event is expected to be transmitted, respectively. Forexample, the wireless power transmission system can configure one ormore antennas to listen for an event transmitted by the wireless powerreceiver client and the wireless power receiver client can configure oneor more antennas to transmit the event to the wireless powertransmission system. At 915, the wireless power receiver clienttransmits the event. At 916, the wireless power transmission systemdetects and/or otherwise receives the event (e.g., beacon).

Next, at 918, the wireless power transmission system identifies theincoming frequency of the beacon and determines phase differential (orvariance) information by comparing the incoming frequency with the localfrequency transmission (e.g., of wireless power signal). A phasedifferential (or variance) indicates a clock mismatch. Again, adetermination is made whether the mismatch in frequency (and thus clocksynchronization) is sufficiently different to warrant an adjustment, at920. For example, if the phase variance is greater than a phase variancethreshold then, at 922, the wireless power transmission system, adjustsits clock (for future scheduled events) specifically for the particularclient in accordance with the phase differential (or variance)information. In some embodiments, the clock will be adjusted by eithermodifying the pre-scalar in a counter, or the fractional part of aFrac-N PLL (phase lock loop). Other adjustments are also possible.

Referring next to FIG. 9B, operations 910-920 are the same as theexample of FIG. 9A, however, in the example of FIG. 9B, rather thanadjusting the wireless power transmission system clock for theparticular client as shown in FIG. 9A, the wireless power transmissionsystem, at 924, notifies the wireless power receiver client by sendingthe phase variance information. The wireless power receiver client, at925, receives the phase variance information and, at 927, adjusts itsclock (for future scheduled events) specifically for the particularclient in accordance with the phase differential (or variance)information.

Among other benefits, the above techniques facilitate automated andrepeated correction of receiver clocks to match those of theirrespective wireless power transmission system. These adjustments allowthe system to maintain tight clock synchronization, thereby preventinglost efficiency due to overly wide timing of beacon exchanges, andlikewise prevent any significant phase variance over time due tomismatched clocks.

FIG. 10 depicts a flow diagram illustrating an example process 1000 forfacilitating synchronization between a wireless power receiver clientand a wireless power transmission system in a wireless power deliveryenvironment, according to some embodiments. A wireless power receiverclient such as, for example, wireless power receiver client 103 of FIG.1 or a wireless power transmission system such as, for example, wirelesspower transmission system 101 of FIG. 1, can, among other functionsperform the example process 1000. For simplicity, the example process1000 is discussed as performed by a wireless power transmission systemin the example of FIG. 10.

To begin, at 1010, the wireless power transmission system monitorsscheduled events related to wireless power transfers in a wireless powerdelivery environment. As discussed herein a scheduled event can be,among other signals, one or more of a beacon signal, a wireless powersignal, or a synchronization signal.

At decision step 1012, the wireless power transmission system determinesif a scheduled event is detected. If so, at 1014, the wireless powertransmission system identifies one or more properties of the scheduledevent and, at 1016, compares the one or more properties of the scheduledevent to expected properties associated with the event to determine adifferential between the wireless power receiver client and the wirelesspower transmission system. At 1016, the wireless power transmissionsystem compares the one or more properties of the scheduled event toexpected properties associated with the event to determine adifferential between the wireless power receiver client and the wirelesspower transmission system.

In some embodiments, the differential comprises an event timedifferential, identifying the one or more properties of the scheduledevent comprises identifying a time that the scheduled event is received,and comparing the one or more properties of the scheduled event to theexpected properties associated with the event to identify the clockdifferential comprises comparing the time that the scheduled event isreceived to a time that the scheduled event is expected to be received.

In some embodiments, the differential comprises a phase differential (orphase variance), identifying the one or more properties of the scheduledevent comprises identifying the incoming frequency of the scheduledevent, and comparing the one or more properties of the scheduled eventto the expected properties associated with the event to identify theclock differential comprises comparing the incoming frequency of thescheduled event to an expected frequency of the scheduled event. Theexpected frequency of the scheduled event can comprise, for example, afrequency at which scheduled events are transmitted.

At decision 1018, the wireless power transmission system determines ifthe differential is greater than a threshold. When the differential isgreater than the threshold, at 1020, the wireless power transmissionsystem reports the differential or synchronizes based on thedifferential. In some embodiments, synchronizing the wireless powerreceiver client and the wireless power transmission system based on thedifferential comprises one or more of adjusting the pre-scalar in acounter or a fractional part of phase lock loop (PLL).

FIG. 11 depicts a block diagram illustrating example components of arepresentative mobile device or tablet computer 1100 with a wirelesspower receiver or client in the form of a mobile (or smart) phone ortablet computer device, according to an embodiment. Various interfacesand modules are shown with reference to FIG. 11, however, the mobiledevice or tablet computer does not require all of modules or functionsfor performing the functionality described herein. It is appreciatedthat, in many embodiments, various components are not included and/ornecessary for operation of the category controller. For example,components such as GPS radios, cellular radios, and accelerometers maynot be included in the controllers to reduce costs and/or complexity.Additionally, components such as ZigBee radios and RFID transceivers,along with antennas, can populate the Printed Circuit Board.

The wireless power receiver client can be a power receiver client 103 ofFIG. 1, although alternative configurations are possible. Additionally,the wireless power receiver client can include one or more RF antennasfor reception of power and/or data signals from a power transmissionsystem, e.g., wireless power transmission system 101 of FIG. 1.

FIG. 12 depicts a diagrammatic representation of a machine, in theexample form, of a computer system within which a set of instructions,for causing the machine to perform any one or more of the methodologiesdiscussed herein, may be executed.

In the example of FIG. 12, the computer system includes a processor,memory, non-volatile memory, and an interface device. Various commoncomponents (e.g., cache memory) are omitted for illustrative simplicity.The computer system 1200 is intended to illustrate a hardware device onwhich any of the components depicted in the example of FIG. 1 (and anyother components described in this specification) can be implemented.For example, the computer system can be any radiating object or antennaarray system. The computer system can be of any applicable known orconvenient type. The components of the computer system can be coupledtogether via a bus or through some other known or convenient device.

The processor may be, for example, a conventional microprocessor such asan Intel Pentium microprocessor or Motorola power PC microprocessor. Oneof skill in the relevant art will recognize that the terms“machine-readable (storage) medium” or “computer-readable (storage)medium” include any type of device that is accessible by the processor.

The memory is coupled to the processor by, for example, a bus. Thememory can include, by way of example but not limitation, random accessmemory (RAM), such as dynamic RAM (DRAM) and static RAM (SRAM). Thememory can be local, remote, or distributed.

The bus also couples the processor to the non-volatile memory and driveunit. The non-volatile memory is often a magnetic floppy or hard disk, amagnetic-optical disk, an optical disk, a read-only memory (ROM), suchas a CD-ROM, EPROM, or EEPROM, a magnetic or optical card, or anotherform of storage for large amounts of data. Some of this data is oftenwritten, by a direct memory access process, into memory during executionof software in the computer 1200. The non-volatile storage can be local,remote, or distributed. The non-volatile memory is optional becausesystems can be created with all applicable data available in memory. Atypical computer system will usually include at least a processor,memory, and a device (e.g., a bus) coupling the memory to the processor.

Software is typically stored in the non-volatile memory and/or the driveunit. Indeed, for large programs, it may not even be possible to storethe entire program in the memory. Nevertheless, it should be understoodthat for software to run, if necessary, it is moved to a computerreadable location appropriate for processing, and for illustrativepurposes, that location is referred to as the memory in this paper. Evenwhen software is moved to the memory for execution, the processor willtypically make use of hardware registers to store values associated withthe software, and local cache that, ideally, serves to speed upexecution. As used herein, a software program is assumed to be stored atany known or convenient location (from non-volatile storage to hardwareregisters) when the software program is referred to as “implemented in acomputer-readable medium”. A processor is considered to be “configuredto execute a program” when at least one value associated with theprogram is stored in a register readable by the processor.

The bus also couples the processor to the network interface device. Theinterface can include one or more of a modem or network interface. Itwill be appreciated that a modem or network interface can be consideredto be part of the computer system. The interface can include an analogmodem, isdn modem, cable modem, token ring interface, satellitetransmission interface (e.g. “direct PC”), or other interfaces forcoupling a computer system to other computer systems. The interface caninclude one or more input and/or output devices. The I/O devices caninclude, by way of example but not limitation, a keyboard, a mouse orother pointing device, disk drives, printers, a scanner, and other inputand/or output devices, including a display device. The display devicecan include, by way of example but not limitation, a cathode ray tube(CRT), liquid crystal display (LCD), or some other applicable known orconvenient display device. For simplicity, it is assumed thatcontrollers of any devices not depicted in the example of FIG. 12 residein the interface.

In operation, the computer system 1200 can be controlled by operatingsystem software that includes a file management system, such as a diskoperating system. One example of operating system software withassociated file management system software is the family of operatingsystems known as Windows® from Microsoft Corporation of Redmond, Wash.,and their associated file management systems. Another example ofoperating system software with its associated file management systemsoftware is the Linux operating system and its associated filemanagement system. The file management system is typically stored in thenon-volatile memory and/or drive unit and causes the processor toexecute the various acts required by the operating system to input andoutput data and to store data in the memory, including storing files onthe non-volatile memory and/or drive unit.

Some portions of the detailed description may be presented in terms ofalgorithms and symbolic representations of operations on data bitswithin a computer memory. These algorithmic descriptions andrepresentations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of operations leading to adesired result. The operations are those requiring physicalmanipulations of physical quantities. Usually, though not necessarily,these quantities take the form of electrical or magnetic signals capableof being stored, transferred, combined, compared, and otherwisemanipulated. It has proven convenient at times, principally for reasonsof common usage, to refer to these signals as bits, values, elements,symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise, as apparent from the followingdiscussion, it is appreciated that throughout the description,discussions utilizing terms such as “processing” or “computing” or“calculating” or “determining” or “displaying” or the like, refer to theaction and processes of a computer system, or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within the computer system's registersand memories into other data similarly represented as physicalquantities within the computer system memories or registers or othersuch information storage, transmission or display devices.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct more specializedapparatus to perform the methods of some embodiments. The requiredstructure for a variety of these systems will appear from thedescription below. In addition, the techniques are not described withreference to any particular programming language, and variousembodiments may thus be implemented using a variety of programminglanguages.

In alternative embodiments, the machine operates as a standalone deviceor may be connected (e.g., networked) to other machines. In a networkeddeployment, the machine may operate in the capacity of a server or aclient machine in a client-server network environment or as a peermachine in a peer-to-peer (or distributed) network environment.

The machine may be a server computer, a client computer, a personalcomputer (PC), a tablet PC, a laptop computer, a set-top box (STB), apersonal digital assistant (PDA), a cellular telephone, an iPhone, aBlackberry, a processor, a telephone, a web appliance, a network router,switch or bridge, or any machine capable of executing a set ofinstructions (sequential or otherwise) that specify actions to be takenby that machine.

While the machine-readable medium or machine-readable storage medium isshown in an exemplary embodiment to be a single medium, the term“machine-readable medium” and “machine-readable storage medium” shouldbe taken to include a single medium or multiple media (e.g., acentralized or distributed database, and/or associated caches andservers) that store the one or more sets of instructions. The term“machine-readable medium” and “machine-readable storage medium” shallalso be taken to include any medium that is capable of storing, encodingor carrying a set of instructions for execution by the machine and thatcause the machine to perform any one or more of the methodologies of thepresently disclosed technique and innovation.

In general, the routines executed to implement the embodiments of thedisclosure, may be implemented as part of an operating system or aspecific application, component, program, object, module or sequence ofinstructions referred to as “computer programs.” The computer programstypically comprise one or more instructions set at various times invarious memory and storage devices in a computer, and that, when readand executed by one or more processing units or processors in acomputer, cause the computer to perform operations to execute elementsinvolving the various aspects of the disclosure.

Moreover, while embodiments have been described in the context of fullyfunctioning computers and computer systems, those skilled in the artwill appreciate that the various embodiments are capable of beingdistributed as a program product in a variety of forms, and that thedisclosure applies equally regardless of the particular type of machineor computer-readable media used to actually effect the distribution.

Further examples of machine-readable storage media, machine-readablemedia, or computer-readable (storage) media include but are not limitedto recordable type media such as volatile and non-volatile memorydevices, floppy and other removable disks, hard disk drives, opticaldisks (e.g., Compact Disk Read-Only Memory (CD ROMS), Digital VersatileDisks, (DVDs), etc.), among others, and transmission type media such asdigital and analog communication links.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” As used herein, the terms “connected,”“coupled,” or any variant thereof, means any connection or coupling,either direct or indirect, between two or more elements; the coupling ofconnection between the elements can be physical, logical, or acombination thereof. Additionally, the words “herein,” “above,” “below,”and words of similar import, when used in this application, shall referto this application as a whole and not to any particular portions ofthis application. Where the context permits, words in the above DetailedDescription using the singular or plural number may also include theplural or singular number respectively. The word “or,” in reference to alist of two or more items, covers all of the following interpretationsof the word: any of the items in the list, all of the items in the list,and any combination of the items in the list.

The above detailed description of embodiments of the disclosure is notintended to be exhaustive or to limit the teachings to the precise formdisclosed above. While specific embodiments of, and examples for, thedisclosure are described above for illustrative purposes, variousequivalent modifications are possible within the scope of thedisclosure, as those skilled in the relevant art will recognize. Forexample, while processes or blocks are presented in a given order,alternative embodiments may perform routines having steps, or employsystems having blocks, in a different order, and some processes orblocks may be deleted, moved, added, subdivided, combined, and/ormodified to provide alternative or subcombinations. Each of theseprocesses or blocks may be implemented in a variety of different ways.Also, while processes or blocks are, at times, shown as being performedin a series, these processes or blocks may instead be performed inparallel, or may be performed at different times. Further, any specificnumbers noted herein are only examples: alternative implementations mayemploy differing values or ranges.

The teachings of the disclosure provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

Any patents and applications and other references noted above, includingany that may be listed in accompanying filing papers, are incorporatedherein by reference. Aspects of the disclosure can be modified, ifnecessary, to employ the systems, functions, and concepts of the variousreferences described above to provide yet further embodiments of thedisclosure.

These and other changes can be made to the disclosure in light of theabove Detailed Description. While the above description describescertain embodiments of the disclosure, and describes the best modecontemplated, no matter how detailed the above appears in text, theteachings can be practiced in many ways. Details of the system may varyconsiderably in its implementation details, while still beingencompassed by the subject matter disclosed herein. As noted above,particular terminology used when describing certain features or aspectsof the disclosure should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects of the disclosure with which that terminology isassociated. In general, the terms used in the following claims shouldnot be construed to limit the disclosure to the specific embodimentsdisclosed in the specification, unless the above Detailed Descriptionsection explicitly defines such terms. Accordingly, the actual scope ofthe disclosure encompasses not only the disclosed embodiments, but alsoall equivalent ways of practicing or implementing the disclosure underthe claims.

While certain aspects of the disclosure are presented below in certainclaim forms, the inventors contemplate the various aspects of thedisclosure in any number of claim forms. For example, while only oneaspect of the disclosure is recited as a means-plus-function claim under35 U.S.C. § 112, ¶6, other aspects may likewise be embodied as ameans-plus-function claim, or in other forms, such as being embodied ina computer-readable medium. (Any claims intended to be treated under 35U.S.C. § 112, ¶6 will begin with the words “means for”.) Accordingly,the applicant reserves the right to add additional claims after filingthe application to pursue such additional claim forms for other aspectsof the disclosure.

The detailed description provided herein may be applied to othersystems, not necessarily only the system described above. The elementsand acts of the various examples described above can be combined toprovide further implementations of the invention. Some alternativeimplementations of the invention may include not only additionalelements to those implementations noted above, but also may includefewer elements. These and other changes can be made to the invention inlight of the above Detailed Description. While the above descriptiondefines certain examples of the invention, and describes the best modecontemplated, no matter how detailed the above appears in text, theinvention can be practiced in many ways. Details of the system may varyconsiderably in its specific implementation, while still beingencompassed by the invention disclosed herein. As noted above,particular terminology used when describing certain features or aspectsof the invention should not be taken to imply that the terminology isbeing redefined herein to be restricted to any specific characteristics,features, or aspects of the invention with which that terminology isassociated. In general, the terms used in the following claims shouldnot be construed to limit the invention to the specific examplesdisclosed in the specification, unless the above Detailed Descriptionsection explicitly defines such terms. Accordingly, the actual scope ofthe invention encompasses not only the disclosed examples, but also allequivalent ways of practicing or implementing the invention.

What is claimed is:
 1. A method of facilitating synchronization betweena wireless power receiver client and a wireless power transmissionsystem in a wireless power delivery environment, the method comprising:monitoring scheduled events related to wireless power transfers in thewireless power delivery environment, wherein the scheduled events areassociated with one or more expected properties; detecting occurrence ofa scheduled event comprising a beacon signal initiated by the wirelesspower receiver client and received by the wireless power transmissionsystem or a wireless power transmission signal initiated by the wirelesspower transmission system and received by the wireless power receiverclient; identifying one or more properties of the scheduled eventincluding a time that the scheduled event is received; and comparing theone or more properties of the scheduled event to expected propertiesassociated with the event including comparing the time that thescheduled event is received to a time that the scheduled event isexpected to be received to determine a clock differential between aclock of the wireless power receiver client and a clock of the wirelesspower transmission system.
 2. The method of claim 1, wherein identifyingthe one or more properties of the scheduled event comprises identifyingan incoming frequency of the scheduled event.
 3. The method of claim 2,wherein comparing the one or more properties of the scheduled event tothe expected properties associated with the event further includescomparing the incoming frequency of the scheduled event to an expectedfrequency to determine a phase differential.
 4. The method of claim 3,wherein the expected frequency of the scheduled event comprises afrequency at which scheduled events are transmitted.
 5. The method ofclaim 1, further comprising: synchronizing the clock of the wirelesspower receiver client with the clock of the wireless power transmissionsystem based on the clock differential.
 6. The method of claim 5,wherein synchronizing the clock of the wireless power receiver clientand the clock of the wireless power transmission system comprisesadjusting a pre-scalar in a counter or a fractional part of a phase lockloop (PLL).
 7. The method of claim 1, further comprising: reporting theclock differential to the wireless power receiver client or the wirelesspower transmission system.
 8. The method of claim 7, further comprising:determining that the clock differential is greater than a threshold; andresponsively reporting the clock differential to the wireless powerreceiver client or the wireless power transmission system orsynchronizing the clock of the wireless power receiver client or theclock of the wireless power transmission system based on the clockdifferential.
 9. A non-transitory computer-readable storage mediumhaving program instructions stored thereon which, when executed by oneor more processors, cause the one or more processors to facilitatesynchronization between a wireless power receiver client and a wirelesspower transmission system in a wireless power delivery environment:monitor scheduled events related to wireless power transfers in thewireless power delivery environment, wherein the scheduled events areassociated with one or more expected properties; detect occurrence of ascheduled event comprising a beacon signal initiated by the wirelesspower receiver client and received by the wireless power transmissionsystem or a wireless power transmission signal initiated by the wirelesspower transmission system and received by the wireless power receiverclient; identify one or more properties of the scheduled event includinga time that the scheduled event is received; and compare the one or moreproperties of the scheduled event to expected properties associated withthe event including comparing the time that the scheduled event isreceived to a time that the scheduled event is expected to be receivedto determine a clock differential between a clock of the wireless powerreceiver client and a clock of the wireless power transmission system.10. The computer-readable storage medium of claim 9, wherein the programinstructions, when executed by one or more processors, cause the one ormore processors to: synchronize the wireless power receiver client andthe wireless power transmission system based on the clock differential.11. The computer-readable storage medium of claim 10, wherein tosynchronize the wireless power receiver client and the wireless powertransmission system based on the clock differential, the one or moreprocessors adjust one or more of a pre-scalar in a counter or afractional part of a phase lock loop (PLL).
 12. The computer-readablestorage medium of claim 9, wherein to identify the one or moreproperties of the scheduled event, the program instructions, whenexecuted by the one or more processors, cause the one or more processorsto identify an incoming frequency of the scheduled event.
 13. Thecomputer-readable storage medium of claim 12, wherein to compare the oneor more properties of the scheduled event to the expected propertiesassociated with the event, the program instructions, when executed bythe one or more processors, cause the one or more processors to comparethe incoming frequency of the scheduled event to an expected frequencyto determine a phase differential.
 14. The computer-readable storagemedium of claim 13, wherein the expected frequency of the scheduledevent comprises a frequency at which scheduled events are transmitted.15. The computer-readable storage medium of claim 9, wherein the programinstructions, when executed by the one or more processors, further causethe one or more processors to: report the clock differential to thewireless power receiver client or the wireless power transmissionsystem.
 16. The computer-readable storage medium of claim 15, whereinthe program instructions, when executed by the one or more processors,further cause the one or more processors to: determine that the clockdifferential is greater than a threshold; and responsively report theclock differential to the wireless power receiver client or the wirelesspower transmission system or synchronize the clock of the wireless powerreceiver client or the clock of the wireless power transmission systembased on the clock differential.
 17. A system for facilitatingsynchronization between a wireless power receiver client and a wirelesspower transmission system in a wireless power delivery environment, thesystem comprising: control circuitry configured to: monitor scheduledevents related to wireless power transfers in the wireless powerdelivery environment, wherein the scheduled events are associated withone or more expected properties; detect occurrence of a scheduled eventcomprising a beacon signal initiated by the wireless power receiverclient and received by the wireless power transmission system or awireless power transmission signal initiated by the wireless powertransmission system and received by the wireless power receiver client;identify one or more properties of the scheduled event including a timethat the scheduled event is received; and compare the one or moreproperties of the scheduled event to expected properties associated withthe event including comparing the time that the scheduled event isreceived to a time that the scheduled event is expected to be receivedto determine a clock differential between a clock of the wireless powerreceiver client and a clock of the wireless power transmission system.18. The system of claim 17, wherein: to identify the one or moreproperties of the scheduled event, the control circuitry is configuredto identify an incoming frequency of the scheduled event, and to comparethe one or more properties of the scheduled event to the expectedproperties associated with the event, the control circuitry is furtherconfigured to compare the incoming frequency of the scheduled event toan expected frequency to determine a phase differential.
 19. The systemof claim 17, wherein the control circuitry is further configured to:synchronize the clock of the wireless power receiver client with theclock of the wireless power transmission system based on the clockdifferential, wherein to synchronize the clock of the wireless powerreceiver client and the clock of the wireless power transmission system,the control circuitry is configured to adjust one or more of apre-scalar in a counter or a fractional part of a phase lock loop (PLL).20. The system of claim 17, wherein the control circuitry is furtherconfigured to: determine if the clock differential to the wireless powerreceiver client or the wireless power transmission system is greaterthan a threshold; and when the clock differential is greater than thethreshold, report the clock differential to the wireless power receiverclient or the wireless power transmission system, or synchronize theclock of the wireless power receiver client and the clock of thewireless power transmission system based on the clock differential.